Zoom lens and imaging device

Abstract

It offers a compact, wide-angle zoom lens. [Solution] The zoom lens is composed of a first lens group L1 with positive refractive power that does not move for zooming, an intermediate group including at least three movable lens groups L2 to L4 that move for zooming, and a rear lens group L5 with positive refractive power that does not move for zooming. The first lens group includes a focusing group. Any one of the movable lens groups in the intermediate group includes an aperture diaphragm SP. When LS is the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end, fw is the focal length of the zoom lens at the wide-angle end, and LP is the distance along the optical axis from the image plane to the exit pupil of the zoom lens at the wide-angle end, with the direction from the image plane towards the object being negative, the conditions 12≦LS / fw≦40 and -0.15≦fw / LP≦-0.01 are satisfied.

Description

Technical Field

[0001] The present invention relates to a zoom lens suitable for imaging.

Background Art

[0002] It is desired that a zoom lens be small in size, have a wide angle of view, and high optical performance. In Patent Document 1, there is disclosed a zoom lens having a first lens group with a positive refractive power that does not move for zooming, a plurality of moving lens groups that move for zooming, and a rear lens group with a positive refractive power that does not move for zooming, which are arranged in order from the object side to the image side. The first lens group of this zoom lens includes a focus group that moves for focusing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A part of the zoom lens disclosed in Patent Document 1 includes an aperture stop in the moving lens group. In this configuration, since the distance from the aperture stop to the image plane becomes long at the wide-angle end, it is difficult to cause light rays to reach the image plane at an appropriate incident angle.

Means for Solving the Problems

[0005] A zoom lens as one aspect of the present invention is composed of a plurality of lens groups, arranged sequentially from the object side to the image side, comprising a first lens group with positive refractive power that does not move for zooming, an intermediate group including at least three movable lens groups that move for zooming, and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The first lens group includes a focus group that moves for focusing. Any one of the movable lens groups in the intermediate group includes an aperture diaphragm. When LS is the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end, fw is the focal length of the zoom lens at the wide-angle end, and LP is the distance along the optical axis from the image plane to the exit pupil of the zoom lens at the wide-angle end, with the direction from the image plane towards the object side being negative, 12 ≤ LS / fw ≤ 40 -0.15 ≤ fw / LP ≤ -0.01 It is characterized by satisfying the following conditions.

[0006] Furthermore, another aspect of the present invention is the zoom lens, 12 ≤ LS / fw ≤ 40 It is characterized by satisfying the following conditions. Furthermore, an imaging device equipped with the above-mentioned zoom lens also constitutes another aspect of the present invention. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a zoom lens that is compact yet has a wide field of view. Furthermore, it is possible to provide a zoom lens with good optical performance. [Brief explanation of the drawing]

[0008] [Figure 1] Cross-sectional view of the zoom lens of Example 1. [Figure 2] Aberration diagrams of the zoom lens of Example 1 at the (A) wide-angle end and (B) telephoto end. [Figure 3] Cross-sectional view of the zoom lens of Example 2. [Figure 4] Aberration diagrams of the zoom lens of Example 2 at the (A) wide-angle end and (B) telephoto end. [Figure 5]Cross-sectional view of the zoom lens of Example 3. [Figure 6] Aberration diagrams of the zoom lens of Example 3 at the (A) wide-angle end and (B) telephoto end. [Figure 7] Cross-sectional view of the zoom lens of Example 4. [Figure 8] Aberration diagrams of the zoom lens of Example 4 at the (A) wide-angle end and (B) telephoto end. [Figure 9] Cross-sectional view of the zoom lens of Example 5. [Figure 10] Aberration diagrams of the zoom lens of Example 5 at the (A) wide-angle end and (B) telephoto end. [Figure 11] Cross-sectional view of the zoom lens of Example 6. [Figure 12] Aberration diagrams of the zoom lens of Example 6 at the (A) wide-angle end and (B) telephoto end. [Figure 13] A diagram showing an imaging device equipped with a zoom lens according to Examples 1 to 6. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described below with reference to the drawings. First, before describing the specific embodiments 1 to 6, we will explain the matters common to each embodiment.

[0010] The zoom lenses of each embodiment are used in various imaging devices such as cinema cameras, broadcast cameras, video cameras, surveillance cameras, digital still cameras, and silver halide cameras. In a zoom lens, a lens group is a collection of one or more lenses that move together or remain stationary during zooming between the wide-angle and telephoto ends. That is, the distance between adjacent lens groups changes during zooming. The lens group may include an aperture diaphragm. The wide-angle and telephoto ends represent the zoom states at the maximum angle of view (shortest focal length) and minimum angle of view (maximum focal length), respectively, when the lens group that moves during zooming is positioned at both ends of the range that is mechanically or controllly movable along the optical axis.

[0011] Figures 1, 3, 5, 7, 9, and 11 each show a cross-section of the zoom lens of Examples 1 to 6 in a state focused on an infinite object (hereinafter referred to as an infinite focus state) and at the wide-angle end. In each figure, the left side is the object side (front side), and the right side is the image side (rear side). OA indicates the optical axis of the zoom lens. Li is the i-th lens group (i = 1, 2, 3,...) counted from the object side, and L1m is the m-th sub-lens group (m = 1, 2, 3,...) counted from the object side in the first lens group L1. L5n or L6n is the n-th sub-lens group (n = 1, 2) counted from the object side in the rear lens group (L5 or L6), and these sub-lens groups are arranged with the widest interval within the rear lens group.

[0012] SP is the aperture stop, and I is the image plane. On the image plane I, the imaging surface (light-receiving surface) of the imaging element in the imaging device or the film surface (photosensitive surface) of the silver salt film is arranged. Also, under the lens group that moves during zooming, the movement trajectory of the lens group during zooming from the wide-angle end to the telephoto end is indicated by an arrow. Further, under the lens group (sub-lens group) that moves during focusing, the movement direction of the lens group during focusing from infinity to the closest distance is indicated by an arrow marked with FOCUS.

[0013] The zoom lens of each example is a zoom lens including a plurality of lens groups, The plurality of lens groups are composed of a first lens group with a positive refractive power that does not move for zooming, which is arranged in order from the object side to the image side, an intermediate group including at least three moving lens groups that move for zooming, and a rear lens group with a positive refractive power that does not move for zooming. The first lens group includes a focus group that moves for focusing. Any one of the moving lens groups in the intermediate group includes an aperture stop.

[0014] Let the distance on the optical axis from the aperture stop at the wide-angle end to the image plane I be LS, the focal length of the zoom lens at the wide-angle end be fw, and the distance on the optical axis from the exit pupil of the zoom lens at the wide-angle end to the image plane be LP. The distance LP is negative in the direction from the image plane toward the object side. At this time, the conditions of the following equations (1) and (2) are satisfied.

[0015] 12 ≤ LS / fw ≤ 40 (1) -0.15 ≤ fw / LP ≤ -0.01 (2) The condition of equation (1) shows an appropriate relationship between the distance from the aperture stop at the wide-angle end to the image plane I and the focal length of the zoom lens in order to obtain a wide-angle view while being small-sized. When LS / fw exceeds the upper limit of equation (1), the distance LS becomes too long with respect to the focal length fw, and the incident angle of the light rays to the image plane I becomes too small. Also, the outermost marginal ray determines the diameter of the lens arranged closest to the image side. At this time, if the distance LS becomes too long, the diameter of the lens increases or the zoom lens becomes large-sized, making it difficult to achieve a wide-angle view, which is not preferable. When LS / fw is below the lower limit of equation (1), the distance from the lens closest to the object side to the aperture stop is too far, increasing the diameter of the lens, making it difficult to achieve both a wide-angle view and a small size, which is not preferable.

[0016] Note that it is more preferable to set the upper limit of equation (1) to 35, 30, 25, 20, or 16. Also, it is more preferable to set the lower limit of equation (1) to 12.5, 13, 13.5, or 14.

[0017] The condition in equation (2) shows the relationship between the distance from the exit pupil to the image plane I at the wide-angle end and the focal length of the zoom lens, in order to allow light rays to be incident on the image plane I at an appropriate angle of incidence. In general, the sensitivity characteristics of the image sensor positioned on the image plane I decrease as the angle of incidence of the light rays increases. Therefore, for good optical performance, it is required that an appropriate angle of incidence of the light rays onto the image plane I be obtained. If fw / LP exceeds the upper limit of equation (2), the exit pupil will be positioned behind the image plane I, and the light rays emitted from the lens closest to the image will be incident on the image plane I at an oblique angle in the direction of the optical axis. As a result, the diameter of the lens closest to the image will increase, making it difficult to attach the zoom lens to the camera, which is undesirable. If fw / LP falls below the lower limit of equation (2), the exit pupil will be too close to the image plane I, and the angle of incidence of the light rays emitted from the lens closest to the image will be too large, which is also undesirable.

[0018] Furthermore, it is more preferable to set the upper limit of equation (2) to -0.02 or -0.03. Also, it is more preferable to set the lower limit of equation (2) to -0.12, -0.10, or -0.08.

[0019] By having the above configuration and satisfying the conditions of equations (1) and (2), it is possible to realize a zoom lens that is compact yet capable of directing light rays to the image plane (image sensor) I at an appropriate angle of incidence, even at a wide angle of view.

[0020] Furthermore, it is preferable that the zoom lens of each embodiment satisfies at least one of the following conditions (3) to (8).

[0021] 0.35 ≤ LE / LR ≤ 0.60 (3) 0.9 ≤ fRR / fR ≤ 2.4 (4) 1.0 ≤ fFR / fR ≤ 3.4 (5) 1.700 ≤ NR ≤ 2.000 (6) 1.00 ≤ f1 / fw ≤ 10.00 (7) -6.00 ≤ f1 / f2 < 0.00 (8) The rear lens group is arranged sequentially from the object side to the image side and consists of a front sub-lens group and a rear sub-lens group that are separated by the widest distance within the rear lens group. In equation (3), LE is the widest distance, and LR is the distance on the optical axis from the object-side surface of the rear lens group to the image-side surface of the rear lens group. In equations (4) to (8), fR is the focal length of the rear lens group, fRR is the focal length of the rear sub-lens group, and fFR is the focal length of the front sub-lens group. NR is the average value of the refractive index at the d line of all lenses included in the rear sub-lens group. f1 is the focal length of the first lens L1. The intermediate group consists of one or two lens groups and has a variator group with negative refractive power as a whole, and f2 is the focal length of the variator group.

[0022] The conditions in equation (3) indicate an appropriate relationship between the total length of the rear lens group, which allows for the insertion and removal of optical units such as extenders for focal length conversion, and the length (spacing) of the space between the front and rear sub-lens groups. If LE / LR exceeds the upper limit of equation (3), the above spacing becomes too wide, resulting in a larger zoom lens, which is undesirable. If LE / LR falls below the lower limit of equation (3), it is undesirable because sufficient space cannot be secured within the rear lens group for inserting an optical unit.

[0023] Furthermore, it is more preferable to set the upper limit of equation (3) to 0.55, 0.50, or 0.45. Also, it is more preferable to set the lower limit of equation (3) to 0.37, 0.38, or 0.39.

[0024] The conditions in equation (4) indicate an appropriate relationship between the focal lengths of the rear sub-lens group and the rear lens group. If fRR / fR exceeds the upper limit of equation (4), the power of the rear sub-lens group becomes too weak, the back focus lengthens, and the overall zoom lens system becomes larger, which is undesirable. If fRR / fR falls below the lower limit of equation (4), the power of the rear sub-lens group becomes too strong, making it difficult to properly set the position of the exit pupil, which is also undesirable.

[0025] Furthermore, it is more preferable to set the upper limit of equation (4) to 2.2, 2.1, or 2.0. Also, it is more preferable to set the lower limit of equation (4) to 1.0.1.1, 1.2, or 1.3.

[0026] The conditions in equation (5) indicate an appropriate relationship between the focal lengths of the front sub-lens group and the rear lens group. If fFR / fR exceeds the upper limit of equation (5), the power of the rear lens group becomes too strong, making it difficult to correct aberrations, which is undesirable. If fFR / fR falls below the lower limit of equation (5), the power of the front sub-lens group becomes too strong, resulting in large variations in aberrations between the front and rear sub-lens groups when an optical unit is inserted and when it is not, which is also undesirable.

[0027] Furthermore, it is more preferable to set the upper limit of equation (5) to 3.2, 3.1, or 3.0. Also, it is more preferable to set the lower limit of equation (5) to 1.2, 1.4, 1.6, or 1.7.

[0028] The conditions in equation (6) indicate the appropriate refractive index at the d line for the lenses (glass material) used in the rear lens group. If the NR exceeds the upper limit of equation (6), it is undesirable because it becomes difficult to correct chromatic aberration as a dispersion difference between the positive and negative lenses cannot be generated. If the NR falls below the lower limit of equation (6), it is undesirable because the refractive index becomes too small, making it difficult to keep the aberration within an acceptable range.

[0029] Furthermore, it is more preferable to set the upper limit of formula (6) to 1.980, 1.960, 1.940, 1.900, or 1.850. Also, it is more preferable to set the lower limit of formula (6) to 1.720, 1.740, 1.760, or 1.780.

[0030] The conditions in equation (7) indicate the appropriate relationship between the focal length of the first lens L1 and the variator group in order to obtain a zoom lens that is compact, yet has a wide angle of view, a high magnification ratio, and high optical performance. If f1 / fw exceeds the upper limit of equation (7), the diameter of the first lens group L1 becomes large, making it difficult to obtain a compact zoom lens, which is undesirable. If f1 / fw falls below the lower limit of equation (7), it becomes difficult to obtain a zoom lens with a wide angle of view and a high magnification ratio, or it becomes difficult to keep aberrations at the wide-angle end within an acceptable range, which is also undesirable.

[0031] Furthermore, it is more preferable to set the upper limit of equation (7) to 9.00, 8.00, 5.00, 3.00, or 2.50. Also, it is more preferable to set the lower limit of equation (7) to 1.50, 1.80, 2.00, or 2.20.

[0032] The conditions in equation (8) indicate an appropriate relationship between the focal lengths of the variator group in the first lens group and the intermediate group. When f1 / f2 satisfies the conditions in equation (8), a refractive power arrangement that is advantageous for a compact, lightweight zoom lens and high magnification can be achieved. If f1 / f2 exceeds the upper limit of equation (8), the power of the variator becomes too weak relative to the power of the first lens group L1, making high magnification difficult, which is undesirable. If f1 / f2 falls below the lower limit of equation (8), the power of the variator group becomes too strong, either resulting in large aberration fluctuations during zooming, or making it difficult to achieve compactness and lightness while suppressing aberration fluctuations, which is also undesirable.

[0033] Furthermore, it is more preferable to set the upper limit of equation (8) to -0.03, -0.06, -0.10, -0.50, -0.70, or -0.80. Also, it is more preferable to set the lower limit of equation (8) to -5.00, -4.00, -3.00, -2.00, or -1.00.

[0034] Furthermore, it is preferable that the zoom lens of each embodiment has at least one of the following configurations.

[0035] The lens closest to the image in the rear sub-lens group preferably has a negative refractive power. This configuration allows the principal point of the rear lens group to be moved towards the object, making it easier to incident light rays on the image plane I at an appropriate angle of incidence.

[0036] The rear sub-lens group is preferably composed of seven or more lenses. Note that a cemented lens formed by joining two lenses is counted as two lenses. This configuration allows for good aberration correction, making it easier to achieve high optical performance.

[0037] The zoom lenses for each embodiment will be described in detail below. Furthermore, numerical examples 1 to 6, corresponding to each of Examples 1 to 6, will be shown after Example 5. [Examples]

[0038] The zoom lens of Embodiment 1 (Numerical Example 1) shown in Figure 1 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0039] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close.

[0040] The second lens group L2 is a variator group with negative refractive power, and it moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each move toward the image side when zooming from the wide-angle end to the telephoto end. The aperture diaphragm SP also moves together with the fourth lens group L4.

[0041] The fifth lens group L5 has a front sub-lens group L51 and a rear sub-lens group L52 arranged in order from the object side to the image side, and is composed of a total of nine lenses. The fifth lens group L5 may also be composed of seven or eight lenses. The front sub-lens group L51 is composed of a joined negative lens and a positive lens, and the rear sub-lens group L52 is composed of a positive lens, a joined negative lens and a positive lens, a joined positive lens and a negative lens, and a joined positive lens and a negative lens. An optical unit such as an extender lens may be inserted in the space between the front sub-lens group L51 and the rear sub-lens group L52.

[0042] Figure 2(A) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens of numerical example 1 at infinity focus and the wide-angle end. Figure 2(B) shows the longitudinal aberrations of the zoom lens of numerical example 1 at infinity focus and the telephoto end.

[0043] In the spherical aberration diagram, Fno indicates the F number, the solid line shows the spherical aberration for the d line (wavelength 587.6 nm), and the dashed line shows the spherical aberration for the g line (wavelength 435.8 nm). The dashed line shows the spherical aberration for the C line (wavelength 656.3 nm), and the long dashed line shows the spherical aberration for the F line (wavelength 486.1 nm). In the astigmatism diagram, the solid line S shows astigmatism on the sagittal image plane, and the dashed line M shows astigmatism on the meridional image plane. The distortion diagram shows distortion on the d line. The chromatic aberration diagram shows lateral chromatic aberration on the g, C, and F lines. The astigmatism and chromatic aberration diagrams show the amount of aberration when the central ray of the light beam at the aperture position is considered the principal ray. ω is the paraxial half-angle of view (°). Spherical aberration is depicted on a scale of 0.2 mm, astigmatism on 0.2 mm, distortion on 5%, and chromatic aberration on 0.05 mm. The explanations above for the aberration diagrams also apply to the aberration diagrams in the following numerical examples. [Examples]

[0044] The zoom lens of Embodiment 2 (Numerical Example 2) shown in Figure 3 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0045] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close.

[0046] The second lens group L2 is a variator group with negative refractive power, and it moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each move toward the image side when zooming from the wide-angle end to the telephoto end. The aperture diaphragm SP also moves together with the fourth lens group L4.

[0047] The fifth lens group L5 has a front sub-lens group L51 and a rear sub-lens group L52 arranged in order from the object side to the image side, and is composed of a total of 10 lenses. The front sub-lens group L51 is composed of a positive lens and a joined negative lens and positive lens, and the rear sub-lens group L52 is composed of a positive lens, a joined positive lens and negative lens, a joined positive lens and negative lens, and a joined positive lens and negative lens. An optical unit such as an extender may be inserted in the space between the front sub-lens group L51 and the rear sub-lens group L52.

[0048] Figure 4(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 2. Figure 4(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 2. [Examples]

[0049] The zoom lens of Embodiment 3 (Numerical Example 3) shown in Figure 5 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0050] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close.

[0051] The second lens group L2 is a variator group with negative refractive power, and it moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each move toward the image side when zooming from the wide-angle end to the telephoto end. The aperture diaphragm SP also moves together with the fourth lens group L4.

[0052] The fifth lens group L5 has a front sub-lens group L51 and a rear sub-lens group L52 arranged in order from the object side to the image side, and is composed of a total of nine lenses. The front sub-lens group L51 is composed of a joined negative lens and a positive lens, and the rear sub-lens group L52 is composed of a positive lens, a joined negative lens and a positive lens, a joined positive lens and a negative lens, and a joined positive lens and a negative lens. An optical unit such as an extender may be inserted in the space between the front sub-lens group L51 and the rear sub-lens group L52.

[0053] Figure 6(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 3. Figure 6(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 3. [Examples]

[0054] The zoom lens of Embodiment 4 (Numerical Example 4) shown in Figure 7 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 are movable lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0055] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close.

[0056] The second lens group L2 is a variator group with negative refractive power, and it moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each move toward the image side when zooming from the wide-angle end to the telephoto end. The aperture diaphragm SP also moves together with the fourth lens group L4.

[0057] The fifth lens group L5 has a front sub-lens group L51 and a rear sub-lens group L52 arranged in order from the object side to the image side, and is composed of a total of nine lenses. The front sub-lens group L51 is composed of a joined negative lens and a positive lens, and the rear sub-lens group L52 is composed of a positive lens, a joined negative lens and a positive lens, a joined positive lens and a negative lens, and a joined positive lens and a negative lens. An optical unit such as an extender may be inserted in the space between the front sub-lens group L51 and the rear sub-lens group L52.

[0058] Figure 8(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 4. Figure 8(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 4. [Examples]

[0059] The zoom lens of Embodiment 5 (Numerical Example 5) shown in Figure 9 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power including the aperture diaphragm SP, and a sixth lens group L6 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, third lens group L3, fourth lens group L4, and fifth lens group L5 are movable lens groups that move for zooming and constitute intermediate groups. The sixth lens group L6 is a rear lens group for image formation and does not move for zooming.

[0060] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close.

[0061] The second lens group L2 and the third lens group L3, together, form a variator group with negative refractive power, and move toward the image side when zooming from the wide-angle end to the telephoto end. The fourth lens group L4 and the fifth lens group L5 each move toward the image side when zooming from the wide-angle end to the telephoto end. The aperture diaphragm SP also moves together with the fifth lens group L5.

[0062] The sixth lens group L6 has a front sub-lens group L61 and a rear sub-lens group L62 arranged in order from the object side to the image side, and is composed of a total of 10 lenses. The front sub-lens group L61 is composed of a positive lens and a joined negative lens and positive lens, and the rear sub-lens group L62 is composed of a positive lens, a joined negative lens and positive lens, a joined positive lens and negative lens and a joined positive lens and negative lens. An optical unit such as an extender may be inserted in the space between the front sub-lens group L61 and the rear sub-lens group L62.

[0063] Figure 10(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 5. Figure 10(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 5. [Examples]

[0064] The zoom lens of Embodiment 6 (Numerical Example 6) shown in Figure 11 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power including the aperture diaphragm SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, third lens group L3, and fourth lens group L4 are moving lens groups that move for zooming and constitute an intermediate group. The fifth lens group L5 is a rear lens group for image formation and does not move for zooming.

[0065] The first lens group L1 consists of a first sub-lens group L11 with negative refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with positive refractive power, arranged in order from the object side to the image side. The second sub-lens group L12 is a focusing group that moves towards the image side when focusing from infinity to close.

[0066] The second lens group L2 is a variator group with negative refractive power, and it moves toward the image side when zooming from the wide-angle end to the telephoto end. The third lens group L3 and the fourth lens group L4 each move toward the image side when zooming from the wide-angle end to the telephoto end. The aperture diaphragm SP also moves together with the fourth lens group L4.

[0067] The fifth lens group L5 has a front sub-lens group L51 and a rear sub-lens group L52 arranged in order from the object side to the image side, and is composed of a total of 10 lenses. The front sub-lens group L61 is composed of a positive lens and a joined positive and negative lens, and the rear sub-lens group L62 is composed of a positive lens, a joined positive and negative lens, a joined positive and negative lens, and a joined positive and negative lens. An optical unit such as an extender may be inserted in the space between the front sub-lens group L61 and the rear sub-lens group L62.

[0068] Figure 12(A) shows the longitudinal aberration at the wide-angle end and in focus at infinity for the zoom lens of numerical example 6. Figure 11(B) shows the longitudinal aberration at the telephoto end and in focus at infinity for the zoom lens of numerical example 6.

[0069] Numerical examples 1 to 6 are shown below. In each numerical example, the surface number i indicates the order of the surfaces from the object side, r is the radius of curvature of the i-th surface (mm), and d is the distance on the optical axis between the i-th surface and the (i+1)-th surface (mm). The (variable) of the distance d indicates the distance that changes during zooming, and the distance according to the focal length is shown in a separate table. nd is the absolute refractive index at 1 atmosphere at the d-line of the optical material between the i-th surface and the (i+1)-th surface. νd is the Abbe number of the optical material between the i-th surface and the (i+1)-th surface with respect to the d-line. The Abbe number νd with respect to the d-line is given by Nd, NF, and NC, respectively, when the refractive indices at the d-line, F-line, and C-line are Nd, NF, and NC. It is expressed as νd = (Nd-1) / (NF-NC).

[0070] θgF is the partial dispersion ratio of the optical material between the i-th plane and the (i+1)-th plane with respect to the g-line and the F-line. The partial dispersion ratio of the g-line and the F-line is given by, when the refractive index at the g-line is Ng, θgF = (Ng - NF) / (NF - NC) It is represented as follows.

[0071] Each numerical example also shows the half-angle of view (°) of the zoom lens, in addition to the specifications such as the focal length and F-number of the entire zoom lens system. BF is the back focus, which indicates the air-equivalent distance from the image-side lens surface (final surface) to the image plane of the zoom lens. The total lens length is the distance along the optical axis from the object-side lens surface (frontmost) to the final surface of the zoom lens, plus the back focus. Furthermore, the lens group data shows the focal length of each lens group.

[0072] The asterisk (*) next to the surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following formula, where X is the displacement from the surface vertex in the direction of the optical axis, H is the height from the optical axis in the direction perpendicular to the optical axis, the direction of light propagation is positive, R is the radius of paraxial curvature, k is the cone constant, and A3 to A16 are the aspherical coefficients. The cone constant and aspherical coefficients "e±x" are multiplied by 10. ±x It means...

[0073]

number

[0074] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd θgF 1* 99476.214 2.10 1.83481 42.7 0.5648 2 26.526 14.50 3* 60.656 1.50 1.80400 46.5 0.5577 4 36.393 15.23 5 -52.015 1.40 1.91650 31.6 0.5911 6 -221.790 0.15 7 148.608 8.53 1.80810 22.8 0.6307 8 -87.769 1.20 9 -1825.418 7.71 1.59522 67.7 0.5442 10* -66.130 3.82 11 330.801 12.62 1.49700 81.5 0.5375 12 -41.914 1.70 1.95375 32.3 0.5905 13 -69.223 0.20 14 250.952 1.70 2.00100 29.1 0.5997 15 52.142 14.71 1.53775 74.7 0.5392 16 -71.364 0.20 17 903.164 6.96 1.65412 39.7 0.5737 18 -72.430 (variable) 19 84.669 0.93 1.85150 40.8 0.5695 20 32.767 3.97 21 -229.954 0.85 1.76385 48.5 0.5589 22 21.414 6.33 1.85478 24.8 0.6122 23 -75.689 0.15 24 -70.958 0.75 2.00100 29.1 0.5997 25 69.265 (Variable) 26 107.428 0.70 1.83481 42.7 0.5648 27 21.997 4.53 1.78880 28.4 0.6009 28 -1529.445 1.99 29 -32.371 0.70 1.90525 35.0 0.5848 30 -367.030 (variable) 31 (aperture) ∞ 5.25 32* 156.160 3.17 1.51633 64.1 0.5353 33 -243.291 0.15 34 49.145 1.10 1.89190 37.1 0.5780 35 35.423 6.28 1.68893 31.1 0.6004 36 -1097.453 (variable) 37 99.723 1.00 1.96300 24.1 0.6212 38 31.772 8.14 1.60311 60.6 0.5415 39 -89.135 41.03 40 71.446 7.08 1.53775 74.7 0.5392 41 -57.888 4.57 42 -92.881 2.50 2.00100 29.1 0.5997 43 48.437 8.07 1.94594 18.0 0.6546 44 -85.330 0.20 45 52.351 8.39 1.49700 81.5 0.5375 46 -35.707 1.00 2.05090 26.9 0.6054 47 45.574 0.19 48 32.012 11.52 1.53172 48.8 0.5631 49 -29.284 1.00 2.00100 29.1 0.5997 50 -60.145 38.36 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4=-2.99616e-06 A 6=-4.30031e-07 A 8=-1.39827e-09 A10=-2.33775e-13 A12= 2.12083e-16 A14=-1.50655e-19 A16=-1.63467e-23 A 3= 1.54769e-05 A 5= 3.14838e-06 A 7= 3.17770e-08 A 9= 3.38993e-11 A11=-9.41310e-15 A13= 2.01907e-18 A15= 2.56691e-21 3rd page k = 0.00000e+00 A 4= 7.64711e-06 A 6= 8.91121e-07 A 8= 9.97080e-09 A10=-6.05496e-12 A12=-6.58184e-14 A14= 8.33873e-17 A16= 2.60566e-20 A 3=-1.33614e-05 A 5=-4.27804e-06 A 7=-1.18897e-07 A 9=-4.13489e-10 A11= 1.59614e-12 A13=-9.76086e-18 A15=-2.57790e-18 Side 10 k = 1.82623e-01 A 4= 1.00880e-06 A 6=-2.39484e-08 A 8=-5.09044e-11 A10= 3.02634e-13 A12= 7.13817e-17 A14= 8.73615e-20 A16= 2.64940e-23 A 3= 7.14913e-07 A 5= 1.43878e-07 A 7= 1.91949e-09 A 9=-3.22022e-12 A11=-8.95740e-15 A13=-4.96495e-21 A15=-2.93804e-21 Page 32 k = 1.89717e+00 A 4=-4.16229e-06 A 6=-1.65595e-08 A 8=-1.32731e-11 A 3= 1.62956e-06 A 5= 1.81038e-07 A 7= 7.51656e-10 Various data Zoom ratio 4.81 Wide-angle, Medium, Telephoto Focal length 11.44 28.45 55.01 F-number 2.72 2.72 3.56 Half-angle (°): 52.30 27.49 15.06 Image height 14.80 14.80 14.80 Lens length 312.24 312.24 312.24 BF 38.36 38.36 38.36 d18 0.99 30.23 42.76 d25 22.60 3.77 2.24 d30 12.78 11.02 1.84 d36 11.76 3.11 1.30 Lens group data Group starting plane focal length 1 1 27.09 2 19 -29.26 3 26 -53.96 4 31 54.38 5 37 80.80 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd θgF 1* 10000.000 2.20 1.83481 42.7 0.5648 2 27.749 11.42 3* 49.085 1.55 1.85150 40.8 0.5695 4 30.638 17.41 5 -46.581 1.45 1.95375 32.3 0.5905 6 -238.739 0.20 7 154.595 7.39 1.80810 22.8 0.6307 8 -96.603 1.48 9 162.699 9.76 1.59522 67.7 0.5442 10* -64.531 2.87 11 -12763.368 10.08 1.43875 94.7 0.5340 12 -42.977 1.60 1.89190 37.1 0.5780 13 -70.707 0.20 14 119.845 1.60 2.00100 29.1 0.5997 15 48.583 16.84 1.43875 94.7 0.5340 16 -50.931 0.20 17 294.717 4.87 1.72342 38.0 0.5836 18 -117.268 (variable) 19 61.564 0.95 1.76385 48.5 0.5589 20 29.525 3.12 21 250.336 0.85 1.76385 48.5 0.5589 22 18.336 5.49 1.78880 28.4 0.6009 23 548.943 0.50 24 -179.274 0.75 1.88300 40.8 0.5667 25 55.379 (Variable) 26 -42.695 0.70 1.80400 46.5 0.5577 27 38.583 2.30 1.78880 28.4 0.6009 28 188.935 (variable) 29 (aperture) ∞ 2.60 30 -85.181 1.00 1.83481 42.7 0.5648 31 98.953 3.28 1.67300 38.3 0.5757 32 -122.559 0.20 33* 38.040 7.45 1.67270 32.1 0.5988 34 -172.105 (variable) 35 72.618 3.45 1.48749 70.2 0.5300 36 1960.555 0.20 37 105.597 1.20 2.00069 25.5 0.6136 38 32.311 13.45 1.51823 58.9 0.5457 39 -98.288 41.34 40 77.401 7.81 1.49700 81.5 0.5375 41 -48.320 0.70 42 67.509 9.11 1.80810 22.8 0.6307 43 -32.241 1.20 2.00100 29.1 0.5997 44 42.196 0.20 45 34.592 9.65 1.72151 29.2 0.6053 46 -31.962 1.87 2.00100 29.1 0.5997 47 33.561 0.20 48 26.154 12.04 1.49700 81.5 0.5375 49 -25.837 1.00 2.00100 29.1 0.5997 50 -50.406 39.11 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4=-5.07434e-05 A 6=-1.24261e-06 A 8=-3.02769e-09 A10=-1.32828e-13 A12= 3.07317e-16 A14= 5.96297e-20 A16= 9.48910e-24 A 3= 1.76927e-04 A 5= 1.13306e-05 A 7= 7.97732e-08 A 9= 5.93685e-11 A11=-1.79443e-14 A13=-2.24213e-18 A15=-1.37391e-21 3rd page k = 0.00000e+00 A 4= 3.96188e-05 A 6= 1.34158e-06 A 8= 1.02871e-08 A10= 1.72902e-11 A12= 8.77815e-15 A14= 2.79450e-17 A16= 4.01300e-21 A 3=-1.26898e-04 A 5=-9.46089e-06 A 7=-1.36404e-07 A 9=-5.39291e-10 A11=-3.05120e-13 A13=-6.78412e-16 A15=-5.34500e-19 Side 10 k = 0.00000e+00 A 4= 3.57746e-06 A 6= 9.61541e-09 A 8= 2.85213e-12 A 3=-8.05567e-06 A 5=-1.68298e-07 A 7=-2.77725e-10 Page 33 k = 0.00000e+00 A 4=-7.04556e-06 A 6= 2.57992e-09 A 8=-2.12778e-12 Various data Zoom ratio 4.81 Wide-angle, Medium, Telephoto Focal length 11.44 28.70 55.05 F-number 2.72 2.72 3.65 Half-angle (°): 52.30 27.28 15.05 Image height 14.80 14.80 14.80 Lens length 315.78 315.78 315.78 BF 39.11 39.11 39.11 d18 0.97 29.48 41.69 d25 20.02 3.40 6.61 d28 15.13 12.41 3.19 d34 16.86 7.69 1.49 Lens group data Group starting plane focal length 1 1 26.27 2 19 -30.57 3 26 -42.49 4 29 61.72 5 35 74.99 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd θgF 1* ∞ 2.10 1.83481 42.7 0.5648 2 25.722 13.33 3* 47.838 1.50 1.80400 46.5 0.5577 4 32.923 16.84 5 -46.067 1.40 1.91650 31.6 0.5911 6 -159.430 1.44 7 198.192 9.14 1.80810 22.8 0.6307 8 -77.040 1.20 9 -953.703 8.14 1.59522 67.7 0.5442 10* -68.369 4.06 11 368.956 12.80 1.49700 81.5 0.5375 12 -43.086 1.70 1.95375 32.3 0.5905 13 -71.080 0.20 14 210.051 1.70 2.00100 29.1 0.5997 15 52.917 15.92 1.53775 74.7 0.5392 16 -64.059 0.20 17 -4613.630 5.61 1.65412 39.7 0.5737 18 -90.339 (variable) 19 59.005 0.93 1.85150 40.8 0.5695 20 30.082 3.53 21 283.197 0.85 1.76385 48.5 0.5589 22 18.896 5.40 1.85478 24.8 0.6122 23 155.907 0.85 24 -162.008 0.75 2.00100 29.1 0.5997 25 75.754 (variable) 26 237.745 0.70 1.83481 42.7 0.5648 27 21.842 4.70 1.78880 28.4 0.6009 28 -276.925 1.68 29 -34.440 0.70 1.90525 35.0 0.5848 30 -2223.598 (variable) 31 (aperture) ∞ 1.76 32* 64.668 3.11 1.51633 64.1 0.5353 33 201.593 0.15 34 66.383 8.49 1.67270 32.1 0.5988 35 -28.560 1.10 1.95375 32.3 0.5905 36 -63.549 (variable) 37 106.501 1.00 1.96300 24.1 0.6212 38 32.885 7.88 1.60311 60.6 0.5415 39 -92.006 41.07 40 79.111 7.16 1.53775 74.7 0.5392 41 -55.643 6.54 42 -60.915 1.64 2.00100 29.1 0.5997 43 57.556 6.95 1.94594 18.0 0.6546 44 -61.444 0.20 45 58.796 8.73 1.53775 74.7 0.5392 46 -34.193 1.00 2.05090 26.9 0.6054 47 47.594 0.53 48 33.356 10.88 1.54072 47.2 0.5651 49 -31.594 1.00 2.00100 29.1 0.5997 50 -56.779 38.29 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4=-8.66041e-06 A 6=-6.51655e-07 A 8=-2.13941e-09 A10=-3.92690e-13 A12= 1.34862e-16 A14= 6.76009e-20 A16= 2.05226e-23 A 3= 4.01043e-05 A 5= 4.78919e-06 A 7= 4.85706e-08 A 9= 5.13358e-11 A11=-8.34995e-15 A13= 3.79478e-20 A15=-2.37657e-21 3rd page k = 0.00000e+00 A 4= 6.15220e-06 A 6= 8.47337e-07 A 8= 1.08176e-08 A10=-1.02156e-13 A12=-5.86602e-14 A14= 1.07347e-16 A16= 3.14158e-20 A 3=-1.82492e-05 A 5=-3.89485e-06 A 7=-1.19578e-07 A 9=-5.16831e-10 A11= 1.40336e-12 A13=-5.08636e-16 A15=-3.14852e-18 Side 10 k = 0.00000e+00 A 4=-1.09260e-06 A 6=-1.32333e-07 A 8=-6.91664e-10 A10= 6.26800e-13 A12=-6.89914e-16 A14=-2.44905e-18 A16=-1.79115e-22 A 3= 3.22437e-06 A 5= 7.63325e-07 A 7= 1.30238e-08 A 9= 1.19548e-11 A11=-2.86604e-14 A13= 8.03265e-17 A15= 3.38170e-20 Page 32 k = 0.00000e+00 A 4=-1.45679e-05 A 6=-1.56223e-06 A 8=-8.55794e-09 A10= 9.91117e-11 A12=-6.35232e-13 A14= 3.63413e-15 A16= 3.13580e-18 A 3= 7.65323e-06 A 5= 5.93543e-06 A 7= 2.06254e-07 A 9=-9.57453e-10 A11= 3.01944e-12 A13=-3.79287e-15 A15=-1.89086e-16 Various data Zoom ratio 4.81 Wide-angle, Medium, Telephoto Focal length 11.44 28.36 55.01 F-number 2.72 2.72 3.64 Half-angle (°): 52.30, 27.56, 15.06 Image height 14.80 14.80 14.80 Lens length 316.37 316.37 316.37 BF 38.29 38.29 38.29 d18 1.00 31.61 44.72 d25 19.51 2.78 3.15 d30 13.79 11.32 2.13 d36 17.25 5.84 1.54 Lens group data Group starting plane focal length 1 1 27.04 2 19 -30.72 3 26 -46.91 4 31 49.89 5 37 80.52 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd θgF 1* 5299.568 2.10 1.83481 42.7 0.5648 2 26.390 14.36 3* 58.658 1.50 1.80400 46.5 0.5577 4 34.583 17.21 5 -47.401 1.40 1.91650 31.6 0.5911 6 -151.774 0.13 7 185.556 9.07 1.80810 22.8 0.6307 8 -77.219 1.20 9 -736.255 7.89 1.59522 67.7 0.5442 10* -65.163 3.98 11 272.869 14.19 1.49700 81.5 0.5375 12 -41.172 1.70 1.95375 32.3 0.5905 13 -66.501 0.21 14 229.770 1.70 2.00100 29.1 0.5997 15 52.199 16.99 1.53775 74.7 0.5392 16 -66.894 0.20 17 1475.240 5.58 1.65412 39.7 0.5737 18 -86.882 (variable) 19* 64.766 0.93 1.85150 40.8 0.5695 20 29.448 3.62 21 378.242 0.85 1.76385 48.5 0.5589 22 18.644 5.33 1.85478 24.8 0.6122 23 192.908 0.72 24 -203.604 0.75 2.00100 29.1 0.5997 25 67.794 (Variable) 26 195.242 0.70 1.83481 42.7 0.5648 27 20.129 4.88 1.78880 28.4 0.6009 28 -237.204 1.74 29 -31.449 0.70 1.90525 35.0 0.5848 30* -421.412 (variable) 31 (aperture) ∞ 1.23 32* 163.720 2.99 1.51633 64.1 0.5353 33 -202.442 0.15 34 57.211 8.44 1.67270 32.1 0.5988 35 -37.304 1.10 1.95375 32.3 0.5905 36 -91.416 (variable) 37 116.199 1.00 1.96300 24.1 0.6212 38 32.690 10.95 1.60311 60.6 0.5415 39 -87.682 41.08 40 60.246 7.67 1.53775 74.7 0.5392 41 -59.558 5.50 42 -65.204 1.00 1.95375 32.3 0.5905 43 48.375 6.55 1.92286 18.9 0.6495 44 -76.368 1.96 45 54.589 7.71 1.53775 74.7 0.5392 46 -38.732 1.00 2.00100 29.1 0.5997 47 36.562 0.21 48 29.834 14.04 1.51823 58.9 0.5457 49 -26.006 1.00 2.00100 29.1 0.5997 50 -45.952 37.99 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4=-3.00133e-06 A 6=-4.71204e-07 A 8=-1.57470e-09 A10=-3.13880e-13 A12= 6.91900e-17 A14=-1.65891e-19 A16=-9.75519e-24 A 3= 2.05042e-05 A 5= 3.37014e-06 A 7= 3.53575e-08 A 9= 3.87228e-11 A11=-6.62646e-15 A13= 5.37587e-18 A15= 2.00120e-21 3rd page k = 0.00000e+00 A 4= 5.38076e-06 A 6= 8.40880e-07 A 8= 1.06309e-08 A10=-8.81100e-13 A12=-6.65923e-14 A14= 7.99567e-17 A16= 2.61196e-20 A 3=-1.21314e-05 A 5=-3.79326e-06 A 7=-1.18698e-07 A 9=-4.99386e-10 A11 = 1.45840e-12 A13 = 1.37723e-16 A15 = -2.55421e-18 The 10th surface k = 0.00000e+00 A4 = 5.55314e-07 A6 = -3.22665e-08 A8 = 7.86250e-11 A10 = 1.00039e-12 A12 = -1.68194e-16 A14 = -2.74405e-19 A16 = 4.69241e-23 A3 = 1.19903e-06 A5 = 2.29863e-07 A7 = 1.72919e-09 A9 = -1.70004e-11 A11 = -2.31999e-14 A13 = 1.92733e-17 A15 = -1.60775e-21 The 19th surface k = 0.00000e+00 A4 = 1.18567e-07 A6 = 1.22085e-09 A8 = -1.22302e-11 A10 = 8.72663e-17 A12 = -3.01996e-19 A14 = 6.91730e-22 A16 = 3.09204e-24 A3 = -2.28028e-07 A5 = -1.85118e-08 A7 = 4.56647e-11 A9 = 5.04436e-13 A11 = 2.05552e-18 A13 = -8.72532e-21 A15 = -3.99022e-23 The 30th surface k = 0.00000e+00 A4 = -7.03741e-08 A6 = 4.14639e-11 A8 = 1.27259e-13 A10 = 5.56621e-15 A12 = 1.73647e-17 A14 = -2.88252e-19 A16 = -2.69879e-21 A3 = 3.00352e-07 A5 = -7.77383e-10 A7 = 6.65859e-13 A9 = -6.10018e-14 A11= 3.09287e-18 A13=-2.52017e-18 A15= 5.64637e-20 Page 32 k = 0.00000e+00 A 4=-6.97696e-06 A 6=-7.89453e-07 A 8=-1.98584e-08 A10=-9.04060e-11 A12=-3.46036e-13 A14=-1.55281e-15 A16=-4.73404e-19 A 3= 2.08347e-06 A 5= 2.49198e-06 A 7= 1.55372e-07 A 9= 1.65304e-09 A11= 4.31418e-12 A13= 2.96113e-14 A15= 4.25677e-17 Various data Zoom ratio 4.81 Wide-angle, Medium, Telephoto Focal length 11.44 28.23 55.01 F-numbers: 2.77, 2.78, 3.62 Half-angle (°): 52.30 27.67 15.06 Image height 14.80 14.80 14.80 Lens length 320.42 320.42 320.42 BF 37.99 37.99 37.99 d18 1.30 29.65 41.79 d25 18.08 2.75 3.29 d30 14.60 12.08 2.75 d36 15.24 4.75 1.38 Lens group data Group starting plane focal length 1 1 25.62 2 19 -28.87 3 26 -47.87 4 31 50.19 5 37 79.50 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd θgF 1* 10000.000 2.20 1.83481 42.7 0.5648 2 27.261 10.90 3* 43.746 1.55 1.85150 40.8 0.5695 4 29.780 16.94 5 -54.008 1.45 1.95375 32.3 0.5905 6 2340.232 0.20 7 126.680 7.91 1.80810 22.8 0.6307 8 -96.980 1.49 9 337.211 8.36 1.59522 67.7 0.5442 10* -58.106 2.89 11 311.073 13.21 1.43875 94.7 0.5340 12 -37.563 1.60 1.95375 32.3 0.5905 13 -52.130 0.20 14 195.594 1.60 2.00100 29.1 0.5997 15 53.751 14.24 1.43875 94.7 0.5340 16 -56.590 0.20 17 -307.119 4.72 1.76634 35.8 0.5792 18 -68.430 (variable) 19 67.923 0.95 1.80400 46.5 0.5577 20 32.553 2.99 21 -4920.510 0.85 1.76385 48.5 0.5589 22 22.528 5.55 1.78880 28.4 0.6009 23 -75.906 (variable) 24 -70.205 0.75 1.88300 40.8 0.5667 25 50.820 (Variable) 26 -32.470 0.70 1.80400 46.5 0.5577 27 29.951 2.65 1.78880 28.4 0.6009 28 433.737 (variable) 29 (aperture) ∞ 2.04 30 -8622.845 1.00 1.83481 42.7 0.5648 31 54.401 3.85 1.67300 38.3 0.5757 32 -599.694 0.20 33* 36.239 7.96 1.57501 41.5 0.5767 34 -138.526 (variable) 35 263.730 2.31 1.48749 70.2 0.5300 36 -187.158 0.20 37 72.439 1.20 2.00069 25.5 0.6136 38 32.243 8.37 1.51823 58.9 0.5457 39 -113.669 41.34 40 74.294 7.17 1.49700 81.5 0.5375 41 -55.213 0.72 42 -216.396 1.20 2.00100 29.1 0.5997 43 25.638 9.15 1.89286 20.4 0.6393 44 -2098.664 0.20 45 29.296 8.30 1.67300 38.3 0.5757 46 -108.576 1.58 2.00100 29.1 0.5997 47 24.135 0.20 48 21.983 14.17 1.43875 94.7 0.5340 49 -24.253 1.00 2.00100 29.1 0.5997 50 -52.485 39.12 Image plane ∞ Aspherical data Front page k = 0.00000e+00 A 4=-4.39106e-05 A 6=-1.26499e-06 A 8=-3.62054e-09 A10=-6.42274e-13 A12= 3.92028e-16 A14= 6.61559e-20 A16= 7.34553e-24 A 3= 1.49036e-04 A 5= 1.08520e-05 A 7= 8.69501e-08 A 9= 8.38675e-11 A11=-1.50177e-14 A13=-3.97045e-18 A15=-1.20551e-21 3rd page k = 0.00000e+00 A 4= 2.70307e-05 A 6= 9.13168e-07 A 8= 9.74093e-09 A10= 2.53181e-11 A12=-1.22397e-14 A14= 7.66186e-17 A16= 2.34551e-20 A 3=-9.70765e-05 A 5=-6.69142e-06 A 7=-1.01727e-07 A 9=-6.68975e-10 A11=-1.89298e-13 A13=-6.65266e-16 A15=-2.28044e-18 Side 10 k = 0.00000e+00 A 4= 3.66220e-06 A 6= 4.66240e-09 A 8= 4.98196e-13 A 3=-5.18478e-06 A 5=-9.23355e-08 A 7=-9.72622e-11 Page 33 k = 0.00000e+00 A 4=-7.27259e-06 A 6= 2.24551e-09 A 8=-2.15475e-12 Various data Zoom ratio 4.81 Wide-angle, Medium, Telephoto Focal length 11.44 28.81 55.02 F-number 2.72 2.72 3.64 Half-angle (°): 52.30 27.19 15.06 Image height 14.80 14.80 14.80 Lens length 307.39 307.39 307.39 BF 39.12 39.12 39.12 d18 0.98 27.50 38.86 d23 1.00 2.87 4.26 d25 23.60 4.18 4.43 d28 11.96 10.23 2.97 d34 14.47 7.22 1.48 Lens group data Group starting plane focal length 1 1 26.71 2 19 -1804.98 3 24 -33.29 4 26 -36.79 5 29 55.77 6 35 70.65 [Numerical Example 6] Unit: mm Surface data Face number rd nd νd θgF 1* -593.245 2.80 1.80100 35.0 0.5864 2 40.556 23.76 3 -134.047 2.00 1.64000 60.1 0.5370 4 131.169 0.19 5 106.867 6.84 1.95906 17.5 0.6598 6 1000.817 1.20 7 212.154 10.59 1.59522 67.7 0.5442 8* -93.369 4.89 9 267.370 5.59 1.43875 94.7 0.5340 10 -263.318 2.00 1.84666 23.8 0.6205 11 2059.769 0.20 12 179.486 5.49 1.49700 81.5 0.5375 13 -461.401 0.20 14 200.496 2.00 1.80518 25.4 0.6161 15 52.168 16.62 1.43875 94.7 0.5340 16 -116.675 0.20 17 98.109 11.35 1.76385 48.5 0.5589 18 -124.523 (variable) 19* -245.470 1.24 2.05090 26.9 0.6054 20 23.985 7.28 21 -24.539 0.85 1.49700 81.5 0.5375 22 52.504 6.17 1.85478 24.8 0.6122 23 -25.337 0.77 24 -22.134 1.00 1.88300 40.8 0.5667 25 -43.940 (variable) 26 -30.558 0.80 1.59522 67.7 0.5442 27 43.554 2.98 1.85896 22.7 0.6284 28 120.762 (variable) 29 (aperture) ∞ 0.20 30* 46.471 6.93 1.89190 37.1 0.5780 31 -171.374 1.50 32 -261.856 1.10 2.00069 25.5 0.6136 33 47.598 8.01 1.55200 70.7 0.5421 34 -99.980 (variable) 35 190.724 7.97 1.48749 70.2 0.5300 36 -45.827 0.25 37 -175.785 10.09 1.76182 26.5 0.6136 38 -27.149 1.10 2.00100 29.1 0.5997 39 -114.183 45.79 40 124.021 8.14 1.48749 70.2 0.5300 41 -46.522 2.04 42 52.765 9.56 1.80810 22.8 0.6307 43 -34.718 0.90 2.00100 29.1 0.5997 44 32.195 1.30 45 28.555 11.51 1.43875 94.7 0.5340 46 -29.213 1.00 1.88300 40.8 0.5667 47 84.000 0.49 48 40.695 11.64 1.48749 70.2 0.5300 49 -23.798 2.00 2.00100 29.1 0.5997 50 -32.954 49.42 Image plane ∞ Aspherical data Front page K = 0.00000e+00 A 4= 1.27215e-06 A 6= 8.56311e-11 A 8=-2.31014e-13 A10 = 2.89318e-17 A12 = 6.96656e-20 A14 = -3.96549e-23 A16 = 6.65814e-27 Face 8 K = 0.00000e+00 A4 = 9.46906e-07 A6 = 1.42931e-10 A8 = -3.43431e-13 A10 = 6.49235e-16 A12 = -7.53367e-19 A14 = 4.15262e-22 A16 = -8.81887e-26 Face 19 K = 0.00000e+00 A4 = 9.53190e-06 A6 = -8.97502e-09 A8 = -4.34509e-11 A10 = 3.58906e-13 A12 = -4.99424e-16 Face 30 K = 0.00000e+00 A4 = -4.13215e-06 A6 = 2.87944e-09 A8 = -1.91722e-12 Various data Zoom ratio 6.92 Wide angle, medium, telephoto Focal length 14.44 53.52 100.00 F-number 2.73 2.73 3.21 Half angle of view (°) 45.70 15.46 8.42 Image height 14.80 14.80 14.80 Overall lens length 350.17 350.17 350.17 BF 49.42 49.42 49.42 d18 0.98 34.03 42.29 d25 29.14 2.36 2.97 d28 8.77 8.39 0.99 d34 13.33 7.45 5.97 Lens group data Group, starting face, focal length 1 1 37.39 2 19 -23.29 3 26 -48.31 4 29 59.45 5 35 75.10 Table 1 summarizes the values of the conditions of formulas (1) to (8) in Numerical Examples 1 to 6. Numerical Examples 1 to 6 satisfy all the conditions of formulas (1) to (8).

[0075] [Table 1]

[0076] [Imaging device] FIG. 11 shows an imaging device provided with the zoom lenses of Examples 1 to 5 as an imaging optical system. 101 is any one of the zoom lenses of Examples 1 to 5. 124 is a camera body. 125 is an imaging device constituted by attaching the zoom lens 101 to the camera body 124. The zoom lens 101 is detachable from the camera body 124. However, the zoom lens 101 may be integrally provided on the camera body 124.

[0077] The zoom lens 101 has, in order from the object side to the image side, a first lens group F, a zoom section LZ, and an imaging lens group R. The first lens group F includes a focus group that moves during focusing. The zoom section LZ is an intermediate group including at least three or more lens groups. On the image side of the zoom section LZ, an aperture stop SP, a lens group R1, and a lens group R2 are arranged. The imaging device 125 has an optical unit IE that can be inserted and removed in the optical path between the lens group R1 and the lens group R2. By inserting the lens unit IE between the lens group R1 and the lens group R2, the range of the focal length of the entire zoom lens 101 can be displaced.

[0078] 114 and 115 are drive mechanisms that move the first lens group F and the lens group included in the zoom section LZ along the optical axis, respectively. 116 to 118 are motors that drive the drive mechanisms 114 and 115 and the aperture diaphragm SP, respectively. 119 to 121 are detection units that detect the position of the first lens group F and the lens group included in the zoom section LZ on the optical axis, and detect the aperture diameter of the aperture diaphragm SP, respectively.

[0079] In the camera body 124, 109 is a glass block such as an optical filter, and 110 is an image sensor that captures the subject image (i.e., the subject through the zoom lens 101) formed by the zoom lens 101. The image sensor 110 is composed of photoelectric conversion elements such as a CCD sensor or a CMOS sensor. 111 and 122 are the camera CPU, which is the processing unit in the camera body 124, and the lens CPU, which is the processing unit in the zoom lens 101, respectively.

[0080] The above embodiments include the following configuration.

[0081] (Composition 1) A zoom lens comprising multiple lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The first lens group includes a focus group that moves for focusing, Any one of the intermediate group's movable lens groups includes an aperture diaphragm, When LS is the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end, fw is the focal length of the zoom lens at the wide-angle end, and LP is the distance along the optical axis from the image plane to the exit pupil of the zoom lens at the wide-angle end, with the direction from the image plane towards the object being negative, 12 ≤ LS / fw ≤ 40 -0.15 ≤ fw / LP ≤ -0.01 A zoom lens characterized by satisfying the following conditions. (Configuration 2) The aforementioned rear lens group is arranged sequentially from the object side to the image side, and is composed of the front sub-lens group and the rear sub-lens group that are separated by the widest distance within the rear lens group. When the widest interval is defined as LE, and the distance along the optical axis from the object-side surface of the rear lens group to the image-side surface of the rear lens group is defined as LR, 0.35 ≤ LE / LR ≤ 0.60 A zoom lens according to configuration 1, characterized by satisfying the following conditions. (Composition 3) When the focal length of the rear lens group is fR and the focal length of the rear sub-lens group is fRR, 0.9 ≤ fRR / fR ≤ 2.4 A zoom lens according to configuration 2, characterized by satisfying the following conditions. (Composition 4) When the focal length of the rear lens group is fR and the focal length of the front sub-lens group is fFR, 1.0 ≤ fFR / fR ≤ 3.4 A zoom lens according to configuration 2, characterized by satisfying the following conditions. (Composition 5) When NR is the average value of the refractive index at the d line of all lenses included in the aforementioned rear sub-lens group, 1.700 ≤ NR ≤ 2.000 A zoom lens according to any one of configurations 2 to 4, characterized by satisfying the following conditions. (Composition 6) When the focal length of the first lens group is f1, 1.00 ≤ f1 / fw ≤ 10.00 A zoom lens according to any one of configurations 1 to 5, characterized by satisfying the following conditions. (Composition 7) The intermediate group is composed of one or two movable lens groups and has a variator group with negative refractive power as a whole, and when the focal length of the variator group is f2 and the focal length of the first lens group is f1, -6.00 ≤ f1 / f2 < 0.00 The zoom lens according to any one of Configurations 1 to 6, characterized by satisfying the following conditions. (Configuration 8) The first lens group includes a first sub-lens group having a negative refractive power, which is arranged closer to the object side than the focus group and does not move for focusing, a second sub-lens group having a positive refractive power as the focus group, and a third sub-lens group having a positive refractive power, which is arranged closer to the image side than the focus group and does not move for focusing. The zoom lens according to any one of Configurations 1 to 7, characterized by having these components. (Configuration 9) The lens closest to the image side in the rear sub-lens group has a negative refractive power. The zoom lens according to any one of Configurations 2 to 5, characterized by this. (Configuration 10) The rear sub-lens group has seven or more lenses. The zoom lens according to any one of Configurations 2 to 5 and 9, characterized by this. (Configuration 11) The plurality of lens groups are arranged in order from the object side to the image side, including the first lens group, a second lens group having a negative refractive power that constitutes the intermediate group and moves during zooming, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power including the aperture stop, and a fifth lens group as the rear lens group. The zoom lens according to any one of Configurations 1 to 10, characterized by being composed of these. (Configuration 12) The plurality of lens groups are arranged in order from the object side to the image side, including the first lens group, a second lens group having a negative refractive power that constitutes the intermediate group and moves during zooming, a third lens group having a negative refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power including the aperture stop, and a sixth lens group as the rear lens group. The zoom lens according to any one of Configurations 1 to 10, characterized by being composed of these. (Configuration 13) A zoom lens including a plurality of lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The first lens group includes a focus group that moves for focusing, Any one of the intermediate group's movable lens groups includes an aperture diaphragm, When LS is the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end, and fw is the focal length of the zoom lens at the wide-angle end, 12 ≤ LS / fw ≤ 40 A zoom lens characterized by satisfying the following conditions. (Composition 14) A zoom lens as described in any one of configurations 1 to 13, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

[0082] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of Symbols]

[0083] L1 First lens group L2 Second lens group L3 Third lens group L4 4th lens group L5 5th lens group L6 6th lens group L11 11th lens group L12 12th lens group L13 13th lens group

Claims

1. A zoom lens comprising multiple lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The first lens group includes a focus group that moves for focusing, Any one of the intermediate group's movable lens groups includes an aperture diaphragm, When LS is the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end, fw is the focal length of the zoom lens at the wide-angle end, and LP is the distance along the optical axis from the image plane to the exit pupil of the zoom lens at the wide-angle end, with the direction from the image plane towards the object being negative, 12 ≤ LS / fw ≤ 40 -0.15 ≤ fw / LP ≤ -0.01 A zoom lens characterized by satisfying the following conditions.

2. The aforementioned rear lens group is arranged sequentially from the object side to the image side, and is composed of the front sub-lens group and the rear sub-lens group that are separated by the widest distance within the rear lens group. When the widest interval is denoted as LE, and the distance along the optical axis from the object-side surface of the rear lens group to the image-side surface of the rear lens group as LR, 0.35 ≤ LE / LR ≤ 0.60 The zoom lens according to claim 1, characterized by satisfying the following conditions.

3. When the focal length of the rear lens group is fR and the focal length of the rear sub-lens group is fRR, 0.9 ≤ fRR / fR ≤ 2.4 The zoom lens according to claim 2, characterized in that it satisfies the following conditions.

4. When the focal length of the rear lens group is fR and the focal length of the front sub-lens group is fFR, 1.0 ≤ fFR / fR ≤ 3.4 The zoom lens according to claim 2, characterized in that it satisfies the following conditions.

5. When NR is the average value of the refractive index at the d-line of all lenses included in the aforementioned rear sub-lens group, 1.700 ≤ NR ≤ 2.000 The zoom lens according to claim 2, characterized in that it satisfies the following conditions.

6. When the focal length of the first lens group is f1, 1.00 ≤ f1 / fw ≤ 10.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

7. The intermediate group is composed of one or two moving lens groups and has a variator group with negative refractive power as a whole, and when the focal length of the variator group is f2 and the focal length of the first lens group is f1, -6.00≦f1 / f2<0.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

8. The first lens group is, A first sub-lens group with negative refractive power, positioned closer to the object than the aforementioned focusing group and not moving for focusing, The second sub-lens group having positive refractive power as the focusing group, The zoom lens according to claim 1, further comprising a third sub-lens group having positive refractive power, which is positioned closer to the image side than the aforementioned focus group and does not move for focusing.

9. The zoom lens according to claim 2, characterized in that the lens on the image side of the rear sub-lens group has a negative refractive power.

10. The zoom lens according to claim 2, characterized in that the aforementioned rear sub-lens group has seven or more lenses.

11. The zoom lens according to claim 1, characterized in that the plurality of lens groups are arranged in order from the object side to the image side, comprising a first lens group, a second lens group with negative refractive power that constitutes the intermediate group and moves during zooming, a third lens group with negative refractive power and a fourth lens group with positive refractive power including the aperture diaphragm, and a fifth lens group as the rear lens group.

12. The zoom lens according to claim 1, characterized in that the plurality of lens groups are composed of a first lens group arranged in order from the object side to the image side, a second lens group with negative refractive power that constitutes the intermediate group and moves during zooming, a third lens group with negative refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power including the aperture diaphragm, and a sixth lens group as the rear lens group.

13. A zoom lens comprising multiple lens groups, The aforementioned group of lenses consists of a first lens group with positive refractive power that does not move for zooming, arranged sequentially from the object side to the image side; an intermediate group including at least three moving lens groups that move for zooming; and a rear lens group with positive refractive power that does not move for zooming, wherein the spacing between adjacent lens groups changes during zooming. The first lens group includes a focus group that moves for focusing, Any one of the intermediate group's movable lens groups includes an aperture diaphragm, When LS is the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end, and fw is the focal length of the zoom lens at the wide-angle end, 12 ≤ LS / fw ≤ 40 A zoom lens characterized by satisfying the following conditions.

14. A zoom lens according to any one of claims 1 to 13, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

Images